Vacuum Table - upgraded and improved
Well, a few months ago, I showed my vacuum table that used O-rings for the seal area. After a few comments from other members and some discussion with a friend, I flip the aluminum plate over and added a different idea of making this a better vacuum table. Here is what I found out on the o-ring, even though I had a good vacuum pump I couldn’t suck the material down to the table. I stopped at one of my friends and he showed me a vacuum table he made and he purchased some seal strips so he gave me a pack and told me how to machine it.
I set down with a CAD system and created what I wanted and after machining it off to be anodized.
This is a shot of the overall plate.
Close-up of the seal in the table.
An extreme close-up of the 1” square – this gives it more surface are to apply some additional suction.
Here is a piece of Corian on the plate before suction is applied. Notice the gap under the Corian.
Once the vacuum is applied
Here is how the seal strip is cut so it forms a pretty good seal on the overlap.
The vacuum pump pulls about 26 in / Hg. I must say that this is far superior to the O-ring design since you have more surface of suction you have mold holding force. I still have the O-ring on the opposite side if needed, but my guess is I probably will not use that side any more.
Interesting, who makes the 'seal strip' material? How much seal material is above the top surface before applying the vacuum?
I have all the materials to make a table except the seal material. I have looked at O-rings several times but was never sure what to order.
Told ya so...
Looks great! Wish I had one...
Actually, several of the commercially available ones I've seen don't use anything special in terms of "seal strip". Instead, they just use square cross section o-ring material. The seal at the corner can be accomplished via overlapping or butting the two pieces up against each other. Both techniques will form a good seal.
( http://www.mcmaster.com/#o-rings/=4jazms "cord stock", square section, etc)
so does this side only have a single inlet?
I bet this side seals better just because of less seal to volume ratio resulting in less seal to leak, and higher pressure on the seal to seal it.
There is 1/32 above the surface when stuffed in the groove. Here is the link for the strip seal.
It is 1/8 thick and 9/32 wide which gives you the compression seal. It works 10 times better than O-ring material.
My goal was to cut the Corian within .020 of the plate and then once cut it is easy to break it out of the Corian. Most of the stuff I will cut will then get some type of round over cutter on a router table. Last night I was cutting something that left a "coupon" in the center when the CNC machine started to cut out a hole in the corian. As the cutter got to the correct depth then it cuts out his "coupon" but instead of the coupon getting cut it just broke it off the .020 thick Corian on the bottom, instant vacuum loss so I hit the stop button. Part was junk but no damage to anything else. I guess now I know how to cut the corian in the future.
When I was looking for seal material I went to a hydraulic seal shop and I was able to purchase rectangular stock by the foot. As long as the material is a closed cell foam it should work just fine. I think I had few options. I told them what I wanted then they brought it out. I still need to build my table. Jeff your looks really nice and I think I need to make one. Thanks for the inspiration.